Modern rapid-fire automatic weapons involve several technical problems in feeding ammunition to such weapons in the quantity and at the rate required during sustained gunfire bursts. Where belt feed systems are used, disengagement of cartridges from the belt must be rapid and reliable, requiring the least possible mechanical operations and the most positive, trouble-free performance characteristics.
The belts used in such systems are required to provide great strength, as long feedlines of heavy-caliber ammunition often are fed to the weapon by devious paths, sometimes nearly vertical, and all the pulling force required to move the belt is transmitted through its individual links. The severe tensile loads transmitted through the belt must not distort the links so as to either loosen or tighten the holding force applied to the cartridges by each link. Thus, loosening of a link may cause a cartridge to fall out of the belt which usually results in separation of the belt at the location of the lost cartridge. Bending of a link such as would tighten its grip on a cartridge or misalign the same in the belt can cause jamming of the weapon due to inability to extract the cartridge from the belt, whereupon the weapon becomes useless.